644372 has 6 divisors (see below), whose sum is σ = 1127658. Its totient is φ = 322184.

The previous prime is 644363. The next prime is 644377. The reversal of 644372 is 273446.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 454276 + 190096 = 674^2 + 436^2 .

It is a d-powerful number, because it can be written as 6³ + 4² + 3⁷ + 4² + 7⁶ + 2¹⁹ .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80543 + ... + 80550.

It is an arithmetic number, because the mean of its divisors is an integer number (187943).

2⁶⁴⁴³⁷² is an apocalyptic number.

It is an amenable number.

644372 is a deficient number, since it is larger than the sum of its proper divisors (483286).

644372 is a wasteful number, since it uses less digits than its factorization.

644372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161097 (or 161095 counting only the distinct ones).

The product of its digits is 4032, while the sum is 26.

The square root of 644372 is about 802.7278492740. The cubic root of 644372 is about 86.3731755433.

The spelling of 644372 in words is "six hundred forty-four thousand, three hundred seventy-two".